Typically, a trunked radio communications system comprises at least one site and a number of subscribers that utilize a radio frequency (RF) resource for communications amongst the subscribers. Each site comprises a number of repeaters that correspond to control channels and voice channels that carry the communications of the system. Generally, a subscriber in the trunked radio communications system is programmed with information relating to how to communicate with the site for access to the RF spectrum for trunked communications. Specifically, the subscriber is programmed with an indication of control channels that the subscriber may use for data communications between the subscriber and the site.
In general, the frequencies that the subscriber has programmed refer to control channels for a specific band plan, where a band plan typically defines the frequency range of the spectrum and how channels are defined in the frequency range. For example, a band plan may specify the numbering scheme of the channels (e.g. numbers between 400 and 500); the center frequency (e.g. 806.0250 MHz); the bandwidth or how far apart each channel will be (e.g. 12.5 kHz); and the spectral mask or how extraneous signals will be attenuated by frequency. If, however, the subscriber moves to a different site that has a different band plan, then the subscriber is not able to not able to utilize the new site for communications until the radio is reprogrammed with the correct control channel information for the new site.
If the subscriber is not programmed properly with an indication of the control channels for a site, then the subscriber is not able to utilize the trunked radio communications system for communications until the radio is reprogrammed with the correct control channel information. Further, if the control channel information is changed for the site, such as the site is changed to a new band plan with new a new set of control channels, then each subscriber associated with the site needs to be reprogrammed with the new control channel information.
Currently, reprogramming of subscribers requires manual effort by radio service personnel so that radio service personnel have direct physical access to a given subscriber. It is not always convenient or even possible, however, for all of the subscribers in a given system to be brought, more or less simultaneously, to a common location to permit the physical installation of the new control channel information when the band plan of sites in the system is changed. As a result, the logistic challenge of reprogramming many subscribers, more or less simultaneously, can be challenging.
Thus, there is a need for an improved method of determining a control channel in a trunked radio communications system.
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